From: Breno Leitao <leitao@debian.org>
To: "Kiryl Shutsemau (Meta)" <kas@kernel.org>
Cc: "Andrew Morton" <akpm@linux-foundation.org>,
linux-mm@kvack.org, linux-kernel@vger.kernel.org,
"Lorenzo Stoakes" <ljs@kernel.org>,
"Mike Rapoport" <rppt@kernel.org>,
"David Hildenbrand" <david@kernel.org>,
stable@vger.kernel.org,
"Sashiko AI review" <sashiko-bot@kernel.org>,
"Liam R. Howlett" <liam@infradead.org>,
"Vlastimil Babka" <vbabka@kernel.org>,
"Jann Horn" <jannh@google.com>,
"Pedro Falcato" <pfalcato@suse.de>,
"Michał Mirosław" <mirq-linux@rere.qmqm.pl>,
"Muhammad Usama Anjum" <usama.anjum@arm.com>,
"Stephen Rothwell" <sfr@canb.auug.org.au>,
"Arnd Bergmann" <arnd@arndb.de>,
linux-fsdevel@vger.kernel.org
Subject: Re: [PATCH 1/6] fs/proc/task_mmu: fix make_uffd_wp_huge_pte() prot-update race
Date: Tue, 10 Nov 2026 08:23:11 -0800 [thread overview]
Message-ID: <avNEgmvYdoukt6MS@gmail.com> (raw)
In-Reply-To: <20260529172331.356655-2-kas@kernel.org>
Hello Kiryl,
On Fri, May 29, 2026 at 06:23:25PM +0100, Kiryl Shutsemau (Meta) wrote:
> The non-hugetlb sibling make_uffd_wp_pte() does this correctly via
> ptep_modify_prot_start() / ptep_modify_prot_commit(). Mirror that
> pattern for the present-PTE branch. The migration case stays as-is --
> migration entries are non-present, so there's no hardware update to
> race against.
I am seeing this on next-20261109 (arm64, PAGE_TABLE_CHECK) while the
pagemap_ioctl kselftest runs next to a workload that migrates pages:
WARNING: mm/page_table_check.c:206 at __page_table_check_ptes_set+0x168/0x178, CPU#21: pagemap_ioctl/894691
Call trace:
__page_table_check_ptes_set+0x168/0x178 (P)
__set_ptes_anysz+0x50/0x240
make_uffd_wp_pte+0x104/0x1c8
pagemap_scan_pmd_entry+0x1b98/0x1df8
walk_pgd_range+0x7b4/0xd00
__walk_page_range+0x108/0x510
walk_page_range_mm_unsafe+0x150/0x3e8
do_pagemap_cmd+0x418/0x7d0
__arm64_sys_ioctl+0xc08/0x1338
given you've touched this recently, I am wondering if you've seen it.
--breno
next prev parent reply other threads:[~2026-11-10 16:23 UTC|newest]
Thread overview: 25+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-05-29 17:23 [PATCH 0/6] userfaultfd/pagemap: pre-existing fixes Kiryl Shutsemau (Meta)
2026-05-29 17:23 ` [PATCH 1/6] fs/proc/task_mmu: fix make_uffd_wp_huge_pte() prot-update race Kiryl Shutsemau (Meta)
2026-06-01 17:55 ` Lorenzo Stoakes
2026-06-01 18:00 ` Lorenzo Stoakes
2026-06-02 6:32 ` Dev Jain
2026-11-10 16:23 ` Breno Leitao [this message]
2026-05-29 17:23 ` [PATCH 2/6] fs/proc/task_mmu: use huge_page_size() in pagemap_scan_hugetlb_entry() Kiryl Shutsemau (Meta)
2026-06-01 18:06 ` Lorenzo Stoakes
2026-06-02 6:36 ` Dev Jain
2026-05-29 17:23 ` [PATCH 3/6] fs/proc/task_mmu: fix hugetlb self-deadlock in pagemap_scan_pte_hole() Kiryl Shutsemau (Meta)
2026-05-29 17:23 ` [PATCH 4/6] mm/huge_memory: preserve pmd_swp_uffd_wp on device-private PMD downgrade Kiryl Shutsemau (Meta)
2026-06-01 0:17 ` Balbir Singh
2026-05-29 17:23 ` [PATCH 5/6] userfaultfd: gate must_wait writability check on pte_present() Kiryl Shutsemau (Meta)
2026-06-01 18:11 ` Lorenzo Stoakes
2026-06-02 8:28 ` Mike Rapoport
2026-05-29 17:23 ` [PATCH 6/6] userfaultfd: build __VMA_UFFD_FLAGS from config-gated masks Kiryl Shutsemau (Meta)
2026-06-01 18:34 ` Lorenzo Stoakes
2026-06-02 8:32 ` Mike Rapoport
2026-06-03 9:17 ` Kiryl Shutsemau
2026-05-30 0:34 ` [PATCH 0/6] userfaultfd/pagemap: pre-existing fixes Andrew Morton
2026-06-01 14:17 ` Kiryl Shutsemau
2026-06-01 15:04 ` David Hildenbrand (Arm)
2026-06-03 9:21 ` Kiryl Shutsemau
2026-06-09 10:30 ` David Hildenbrand (Arm)
2026-06-01 17:38 ` Lorenzo Stoakes
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